Virtual memory and dlmalloc

kernel/paging/x86_64/paging.c

@@ -0,0 +1,124 @@
+#include <stdint.h>
+#include <stddef.h>
+#include <limits.h>
+#include "paging/paging.h"
+#include "hal/hal.h"
+#include "bootinfo/bootinfo.h"
+#include "util/util.h"
+#include "kprintf.h"
+
+enum {
+  PF_PRESENT      = 1<<0,
+  PF_READWRITE    = 1<<1,
+  PF_USER         = 1<<2,
+  PF_WRITETHROUGH = 1<<3,
+  PF_NOCACHE      = 1<<4,
+  PF_ACCESS       = 1<<5,
+  PF_DIRTY        = 1<<6,
+  PF_PAGESIZE     = 1<<7,
+  PF_ATTRTAB      = 1<<7,
+  PF_GLOBAL       = 1<<8,
+  PF_SHARED       = 1<<9,
+  PF_CACHE_WC     = PF_ATTRTAB | PF_WRITETHROUGH,
+};
+
+#define PGSHIFT_PML4E   39
+#define PGSHIFT_PDPTE   30
+#define PGSHIFT_PDE     21
+#define PGSHIFT_PTE     12
+#define PGMASK_ENTRY    0x1ff
+#define PGMASK_OFFSET   0x3ff
+
+#define BITS_TO_VIRT_ADDR(pml4_index, pdpte_index, pd_index, pt_index)         \
+  (((uint64_t)pml4_index << PGSHIFT_PML4E) |                                   \
+   ((uint64_t)pdpte_index << PGSHIFT_PDPTE) |                                  \
+   ((uint64_t)pd_index << PGSHIFT_PDE) | ((uint64_t)pt_index << PGSHIFT_PTE))
+
+// Workaround repeated characters
+#define AMD64_MM_STRIPSX(a) ((uintptr_t)(a) & 0xFFFFFFFFFFFF)
+#define AMD64_MM_ADDRSX(a)                                                     \
+  (((uintptr_t)(a) & (1ULL << 47)) ? (0xFFFFFF0000000000 | ((uintptr_t)(a)))   \
+                                   : ((uintptr_t)(a)))
+
+// Virtual address' macros
+#define PML4E(a) (((a) >> PGSHIFT_PML4E) & PGMASK_ENTRY)
+#define PDPTE(a) (((a) >> PGSHIFT_PDPTE) & PGMASK_ENTRY)
+#define PDE(a) (((a) >> PGSHIFT_PDE) & PGMASK_ENTRY)
+#define PTE(a) (((a) >> PGSHIFT_PTE) & PGMASK_ENTRY)
+
+#define PTE_ADDR_MASK 0x000ffffffffff000
+#define PTE_GET_ADDR(VALUE) ((VALUE) & PTE_ADDR_MASK)
+#define PTE_GET_FLAGS(VALUE) ((VALUE) & ~PTE_ADDR_MASK)
+
+#define PAGE_MASK(x) ((1 << (x)) - 1)
+
+#define USER_STACK_PAGES 2048
+#define PAGE_SIZE 0x1000
+#define PAGE_SIZE_LARGE 0x200000
+#define PAGE_SIZE_HUGE 0x40000000
+
+#define P_PHYs_ADD(x) ((x) & ~0xfff)
+
+uint64_t *global_page_dir = NULL;
+
+void paging_init(void) {
+  uint64_t pdphys = 0;
+  asm volatile("movq %%cr3, %0" : "=r"(pdphys));
+  if (!pdphys) {
+    ERR("paging", "could not get default page dir\n");
+    hal_hang();
+  }
+
+  uint64_t pdvirt = pdphys + BOOT_INFO.hhdm_off;
+  global_page_dir = (uint64_t *)pdvirt;
+
+  LOG("paging", "global_page_dir = %p\n", global_page_dir);
+}
+
+size_t _paging_virt2phys(uint64_t *pgdir, size_t virtaddr) {
+  if (!pgdir) return 0;
+
+  if (virtaddr >= BOOT_INFO.hhdm_off
+   && virtaddr <= (BOOT_INFO.hhdm_off + MAX(BOOT_INFO.memmap_total, UINT32_MAX))) {
+    return virtaddr - BOOT_INFO.hhdm_off;
+  }
+
+  size_t virtaddr_init = virtaddr;
+  virtaddr &= ~0xfff;
+
+  virtaddr = AMD64_MM_STRIPSX(virtaddr);
+
+  uint32_t pml4idx = PML4E(virtaddr);
+  uint32_t pdpidx = PDPTE(virtaddr);
+  uint32_t pdidx = PDE(virtaddr);
+  uint32_t ptidx = PTE(virtaddr);
+
+  if (!(pgdir[pml4idx] & PF_PRESENT)) {
+    return 0;
+  }
+
+  size_t *pdp = (size_t *)(PTE_GET_ADDR(pgdir[pml4idx]) + BOOT_INFO.hhdm_off);
+
+  if (!(pdp[pdpidx] & PF_PRESENT)) {
+    return 0;
+  }
+
+  size_t *pd = (size_t *)(PTE_GET_ADDR(pdp[pdpidx]) + BOOT_INFO.hhdm_off);
+
+  if (!(pd[pdidx] & PF_PRESENT)) {
+    return 0;
+  }
+
+  size_t *pt = (size_t *)(PTE_GET_ADDR(pd[pdidx]) + BOOT_INFO.hhdm_off);
+
+  if (pt[ptidx] & PF_PRESENT) {
+    return (size_t)(PTE_GET_ADDR(pt[ptidx]) + ((size_t)virtaddr_init & 0xfff));
+  }
+
+  return 0;
+}
+
+size_t paging_virt2phys(size_t virtaddr) {
+  return _paging_virt2phys(global_page_dir, virtaddr);
+}
+